Electrical protector device



G. H. BRQDIE ELECTRICAL PROTECTOR DEVICE Filed Oct. 30, 1930 March 21, 1933.

Patented Mar. 1933 UNITED STATES PATENT OFFICE GEORGE E. BBODIE, 0F RIVERSIDE, ILLINQIB, ASSIGNOB '10 wns'rm ELECTRIC CO!- PANY, INCORPORATED, 01 NEW YORK, N. Y, A CORPORATION 01' NEW Your ELECTRICAL raomc'ron DEVICE 'Application med October-$0, mo. Serial No. 492,190. g

This invention relates to electrical protector devices, and more particularly to elec: trical protector block assemblies or hghtmng arresters for tele hone systems.

An object of th an electrical protector device which is simple in construction, -very eflicient for the purpose intended, and economical to manu-,

facture. This invention contemplates the provlsion of a pair of protector blocks formed of a conducting material; for example, carbon separated by' a coating of non-conducting material which is carbonizable under certam electrical conditions forestabli'shing an electrical 'conducting path between the two blocks. Specifically oneof the blocks has a groove in one surface thereof defining an arcing area which is spaced from the sur-' face of the opposing block, the remainder of the surface of the block outside of the groove being provided with a coating of non-conducting material for insulating the blocks from each other and for spacing the arcing area from the-opposin block by the thickness of the coating whic may be applied through successive spraying opera tions.

- A feature of this invention is the formation of a fillet of insulating material in the groove oft the insulatin block terminating at the farthest points rom the companion block to prevent the current arcing from the 'outer edge of the groove and consequent premature grounding of the blocks. Another feature. of this invention is the rovision of an. insulating material whic is carbonizabIe-by the passage of current when an abnormal surge of energy occurs to connect the two blocks electrically after such discharge and establish a discharge path.

It is believed that a complete understanding of the invention may be had by reference to the following description, taken in conjunction with the accompanying drawing, wherein Fig. 1 is a plan view of a protector device the grooved surface of block 22 (Fig. 5),

embodying features of the invention;

Fig. 2 is a sectional view taken along line 2-2 of Fig. 1; I

Fig. 3 is a top plan view ofthe grooved block;

Fig. 4 is a sectional view taken along the. line 4-4 of Fig. 3; is invention is to provide Fig. 5 is a longitudinal sectional view of the grooved block during an intermediate stage of its manufacture, and

Fig. 6 is a cross-sectional view of the protector block assembly.

Referring to the drawing in which the same reference characters indicate similar arts in these views, and particularly in igs. 1 and 2, a protector device is desig nated enerally by the reference numeral 10, an comprises a base member 11 which is provided with a pair of terminals 1212, by which the protector device may be attached to a communicating line (not shown), and a terminal 13 which is connected to ground. Thelbase member 11 has a central aperture 14 through which a metallic member 15 extends, the metallic member being electrically connected to the ground terminal 13. Connected to the terminals 12-12- and extending through the aperture 14 are resilient contact members 16 which are equally spaced from the metallic member 15. Two protector block assemblies are mounted between the resilient contact members 16 and are held thereby in close engagement with the metallic member 15, as shown. in

. 21, while the other block indicated at 22 is thicker in general formation than block 20 and is provided with a continuous groove or moat 23 in one surface thereof which forms an arcing surface 24 positioned centrally on the surface of the block.

insulating material is disposed upon a portionofthe wall of the groove 23, the side walls 25, and the end walls 26. This insulating material, indicated at 27, con-- densation product in the form of a varnish.

In placing the insulating material upon the grooved-block 22, the arcing surface 24 is shielded bya cover 28, which extends over the inner half of the. groove 23. The insulating material is sprayed on the block 22 in liquid form, and after sprayin each coating of material u on the block, su lcient time is allowed for t e material to dry. A desired number of coatings of the insulating material are disposed in this manner upon the aforementioned surfaces of the block 22 until the insulating material is -'of a predetermined thickness, preferably about threethousandths (.003) of an inch. A continuous spraying operation may be had by directin a warm. air blast in contact wit the walls ing sprayed, thus drying the insulating material almost as soon as it is deposited upon the" block.

' The use of the cover 28 makes it possible to coat the. selected portions of the block without coating either the island 24 or the inner walls of the groove 23; that is, the portions of the walls of the groove adjacent the island, the outer 'portions of the groove being coveredwith the insulated material as indicated at 29 (Fig. 5).

' In assembling the protector blocks within the protector device shown -in Fi s.- 1 and 2, one of the blocks 20 is place .upon the grooved face of a block 22 and while in this relation the two blocks are inserted between the metallic member 15 and one of the resilient contact memberslti, the latter be- 0 ing receivable in a longitudinally extendin groove 32 of the block 22. Another set 0 the blocks 20 and 22 are disposed in a like manner between the metallic member 15 and the other resilient contact member 16, completing the assembly of the protector device.

With this protector device assembly connected across a communicating line of a telephone system each side of the line is insulated from the ground terminal 13 by the insulating material 21, which also spaces the arcing surface 24 a desired distance of approximately .003 of an inch from the opposing block 20'. If an abnormal surge of energy occurs in either side of the communicating line, the excess current will pass through the terminal 12, the resilient contact member 16, the adjacent block assembly and through the metallic member 15 to ground at '13. The arcing surface 24 of the block 22 and the adjacent surface of the block 20 are positioned sufiiciently close together that the excess voltage will arc across, thus temporarily connecting the line circuit to the ground 13, and relieving the line of the excess voltage. This groundingzof the The groove 23 and the block 22 are partly covered with the insulating material 27, which forms a fillet adjacent the outer portion of the grooved surface to prevent the current arcing from the outer edge of the groove 23 to the block 20. Since the outer wall of the groove 23 is covered with the insulating material 27, the inner edge of the insulating material terminates at points farthest from the companion block 20, when the two blocks are in assembled relation. If the insulatin material terminated at the upper edge of t e groove 23, and the excess current arced across the ga adjacent the edge of the insulating material, that portionof the insulating material would be carbonized and a permanent short circuit between the blocks 20 and 22 would result. This is obviated, however, by extending the material into the groove 23 where itterminates at the farthest position from the block 20 to eliminate the arcing across 'of the excess current at a position adjacent the insulating material unless prolonged surge of hi;

the insulating material will be has subsided the carbonized material continues to connect the line to ground.

When the insulating material has been. carbonized, or when a short circuit occurs due to the collection of carbon particles between the blocks 20 and 22, these blocks may be cleaned of the carbonized material and the block v22 again provided with a coating of insulating material of a desired thickness, or the blocks may be discarded and new blocks inserted in their places.

Although the invention has been described with reference to a particular embodiment, it may be embodied in other forms without departing from the spirit and scope thereof as defined in the following claims.

What is claimed is: 1. In an electrical protector device, a block having a groove therein defining an arcing surface, insulating material disposed upon said block around and within a portion of said groove, and a block having a plain surface spaced from said grooved block by said insulating material.

2. In an electrical protector device, a

block having a continuous groove therein forming an island portion, an insulati material disposed upon said block aroun and within a portion of said groove, and a' block having a plain surface spaced from the island portion of said grooved block by said insulatin material.

3. In an e ectrical protector device, a block having a groove therein defining an arcing surface, a coating of insulating material dis (1 upon the block and in a rtion of t e groove, and a companion b ock spaced, from said grooved block by said insulating material.

4. In an electrical protector device, a' block formed of conducting material and ha ving, a groove in one surface thereof short of the outer edge thereof and an insulating material disposed upon the grooved surface of the block, around said groove and over the outer wall of the groove.

5. In an electrical protector device, a block formed of conducting material and having a groove in one surface thereof short of the outer edge thereof, an insulating material disposed upon the grooved surface of the block around said groove and over the outer wall of the oove, and a companion block disposed ad acent the insulatin material of. the grooved block, the insu ating material in said groove preventing arcing across at the outer edges of the groove.

6. In an electrical protector device, a block formed of conducting material and having a groove in one surface thereof short of the outer edge thereof, and in insulating material integral with the grooved surface j of said block-positioned around said groove and over the outer wall of the groove.

7. In an electrical protector device, a block formed of conducting material and having a groove in one surface thereof short of the outer edge thereof, an insulating material integral with the grooved surface of said block positioned around said groove, over the outer wall of the oove, and over the peripheral wall of sai block.

In witness whereof, I hereunto subscribe by name this 18th day ofoctober, A. D.

GEORGE H. BRODIE. 

